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Raspberry Pi开发之旅-空气温湿度检测(DHT11)

一、首先,简单介绍下DHT11:

DHT11是一个温湿度传感器,分为3个接口,分别为:VCC, DATA, GND

 引脚号名称类型说明
1 VCC 电源 +级,输入3V-5.5V
2 DATA 数据输出 输出引脚
3 GND 接地 接地引脚

之前看网上说,需要在DHT11VCCDATA之间加一个电阻,经试验完全不需要。

二、引脚连接:

1.VCC接上3V,可以选择1口或者17

2.DATA接上GPIO口,我选的是GPIO4,第7

3.GND接上接地口,我选的是第14

三、Python获取温湿度:

#!/usr/bin/python
import RPi.GPIO as GPIO
import time

channel =4 
data = http://www.mamicode.com/[]"sensor is working."
print data

humidity_bit = data[0:8]
humidity_point_bit = data[8:16]
temperature_bit = data[16:24]
temperature_point_bit = data[24:32]
check_bit = data[32:40]

humidity = 0
humidity_point = 0
temperature = 0
temperature_point = 0
check = 0

for i in range(8):
  humidity += humidity_bit[i] * 2 ** (7-i)
  humidity_point += humidity_point_bit[i] * 2 ** (7-i)
  temperature += temperature_bit[i] * 2 ** (7-i)
  temperature_point += temperature_point_bit[i] * 2 ** (7-i)
  check += check_bit[i] * 2 ** (7-i)

tmp = humidity + humidity_point + temperature + temperature_point

if check == tmp:
  print "temperature :", temperature, "*C, humidity :", humidity, "%"
else:
  print "wrong"
  print "temperature :", temperature, "*C, humidity :", humidity, "% check :", check, ", tmp :", tmp

GPIO.cleanup()

四、展示结果:

root@raspberrypi:/data/basedata# python/dht11.py
sensor is working.
[0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0]
temperature : 23 *C, humidity : 93 %

为了测试结果是否准确,我把手指放到传感器上,测试的数据为:

root@raspberrypi:/data/basedata/python# python dht11.py
sensor is working.
[0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1]
temperature : 36 *C, humidity : 95 %

测试无误~

PS: 如果你用的是DS18B20,需要做以下动作:

root@raspberrypi:/# apt-get update
root@raspberrypi:/# apt-get upgrade #更新内核
root@raspberrypi:/# reboot
root@raspberrypi:/# vi /boot/config.txt #在最后一行手动添加:dtoverlay=w1-gpio-pullup,gpiopin=4 来支持新系统读取w1总线设备
root@raspberrypi:/# modprobe w1-gpio #确认设备是否生效
root@raspberrypi:/# modprobe w1-therm
root@raspberrypi:/# cd /sys/bus/w1/devices/

 

Raspberry Pi开发之旅-空气温湿度检测(DHT11)